Hi Amit,
I think audit records can be recorded regarding design to _aud tables in database.
Could you please check if audit is enabled?
In Automation Studio, Administration tab > System Settings > Audit Design Changes.
If you use latest RA, Administration menu > System Settings > Audit Design Changes in ROC.
When update the setting, you need to restart RA service on management server.
Deployment history is not audit records. The data is used to show dashboard report, so no functions to purge the data, I suppose.
Regards
Yas